One hundred local populations of maize from four different agroecological zones in Guipuzcoa, in Northern Spain were characterized according to Papadaki's classification. Their morphological characteristics were also studied and related with the type of soil of the areas of origin 81% of the populations belonged to areas with Continental Mild Hot and Mild Hot climate, and 96% of them were collected in areas with soils Luvisol and Cambisol. Significant effects of the climate in the area collecting were found for 12 of the 15 morphological and phenological traits analyzed. Morphological and phenological differences appeared between populations collected in areas with different soil type. The results suggest that the use of ecological variables at the sites of origin of the populations can reveal their possibilite of adaptation. The also facilitates the selection of maize populations to be used in breeding programmes for specific agroecological new areas.